Howdy,
A check engine warning came up with a vacuum leak code, though the techician could not find a leak. (Car was performing well too). The O2 sensor was replaced a few weeks earlier.

Also the heater blows only cold, although the hoses from the engine into the dash are hot, as is the hose from the engine to the radiator. Engine seems to warm up fine.

These symptoms have now appeared and slowly are worsening:

1) Surging idle from 1000-2000 rpm only for a few minutes after starting, then smooths out.

2) hissing for a few seconds from glove box area after engine is turned off, as well as for a few seconds during acceleration.

3) no lack of power is noted


I was told I would most likely need a new heatr core and have it looked at again for a vacuum leak or a faulty sensor.

Seems to me this may be just a leak one of the heating system components.


I would appreciate a few suggestions as to the most likely source of the malfunction before an exhaustive and expensive search for a vacuum leak and heater core replacement.

An estimate of time required for an average do-it-yourselfer to disassemble/reassemble for repair would also be great.

Thanks